The proposed research will focus on quantifying the influence of the early social and acoustic environment on the development of bottlenose dolphins' individually-distinctive signature whistles. Vocal learning is critical for human language development but plays a much smaller role in the vocal development of most non-human terrestrial mammals. However, learning appears to be involved in the development of dolphin signature whistles and preliminary evidence indicates that the early social environment influences the learning process. The role of experience in signature whistle development will be evaluated by recording the acoustic and social environments of free-ranging calves. The research will take place in Sarasota FL, where a more than 25-year project has tracked the life-history of the dolphin population. To determine if the calves are matching environmental models, each calf will be assigned a possible model group consisting of the whistles they heard during focal animal samples. The calves' signature whistles will be compared to the whistles in their own model group and in the model groups of other calves. If a calf's signature whistle is most similar to whistles of unrelated dolphins in its own model group, it can be concluded that learning plays a role in signature whistle development. Detailed behavioral and acoustic measurements will be used to evaluate the social and acoustic factors that affect each calf's choice of model.